Symptoms of U0105
- Check-engine light, often with a misfire feel from one cylinder.
- Rough idle, hesitation, or a slight loss of power.
- Higher fuel use, or in some cases a fuel smell.
Common causes of U0105
- A stuck, leaking, clogged, or electrically failed injector.
- Injector wiring, connector, or driver-circuit faults.
- Low fuel pressure or contamination affecting injector behaviour.
Useful checks before replacing parts
- Check power and ground at the fuel injector control module first, including its fuses and any relay that feeds it, because an unpowered module is silent in exactly the same way as a failed one.
- Establish whether one module is missing from the network or several are, since a whole missing segment points at bus wiring or a gateway rather than at the named controller.
- Load-test the battery and check charging voltage before anything else, because low system voltage drops modules offline and sets communication codes across unrelated systems.
How serious is U0105, and can you keep driving?
- Urgency
- Moderate to high
- Safe to drive?
- Short distances only, and not if the engine is shaking.
An injector fault ends up in one of two places: too little fuel in a cylinder, or too much. Too little leans that cylinder out under load. Too much washes the bore and sends unburnt fuel into the catalytic converter, which is the expensive failure. If the fault has turned into a felt misfire, treat it with the urgency of a misfire code rather than a sensor code.
Clearing U0105, and making it stay gone
Clearing U0105 with a scan tool switches the lamp off; it does not fix anything, and it throws away the freeze-frame snapshot the car saved when the fault set. That snapshot is the most useful diagnostic evidence you have, because it records the load, RPM and temperature at the moment the test failed. Read it before you erase it.
Left alone, the lamp goes out on its own once the monitor that failed runs and passes on three consecutive driving cycles. The code stays in history after that, which is how a workshop can still see it. Disconnecting the battery is not a shortcut — it clears the stored codes and every learned fuel-trim value with them, so the car relearns from scratch and the underlying fault simply sets the code again.
On vehicles from roughly 2010 onward there is also a permanent DTC, which no scan tool can erase at all. It clears only when the monitor genuinely passes. That is deliberate: it stops a code being wiped in the car park outside an emissions test.
What U0105 costs to put right
There is no honest single figure for U0105, and any page that gives you one is guessing. The code names a circuit or a failed monitor, not a part — the same code can be a chafed wire, a connector full of water, or the component itself, and those are three very different bills.
The number worth budgeting for is diagnostic time. An hour of it is almost always cheaper than the second part you buy after the first one does not fix it, and parts fitted on a guess are rarely refundable once installed. If you are getting a quote, ask what the diagnosis found rather than what is being replaced — a injector fault traced to a specific cause is a repair, and a list of parts is a hopeful shopping list.
Questions people ask about U0105
What does U0105 mean?
U0105 sets when the reporting module stops receiving expected messages from the fuel injector control module. The module may be dead, unpowered, or simply unable to reach the network — the code cannot tell those apart on its own.
Can I drive with U0105?
Short distances only, and not if the engine is shaking. An injector fault ends up in one of two places: too little fuel in a cylinder, or too much. Too little leans that cylinder out under load. Too much washes the bore and sends unburnt fuel into the catalytic converter, which is the expensive failure. If the fault has turned into a felt misfire, treat it with the urgency of a misfire code rather than a sensor code.
What causes U0105?
The usual candidates are a stuck, leaking, clogged, or electrically failed injector; injector wiring, connector, or driver-circuit faults; low fuel pressure or contamination affecting injector behaviour. The code tells you which test failed, not which of those did it — that is what the checks on this page are for.
Will U0105 clear itself?
Left alone, the lamp goes out on its own once the monitor that failed runs and passes on three consecutive driving cycles. The code stays in history after that, which is how a workshop can still see it. Disconnecting the battery is not a shortcut — it clears the stored codes and every learned fuel-trim value with them, so the car relearns from scratch and the underlying fault simply sets the code again.
Does U0105 mean I need to replace a part?
Do not order the fuel injector control module on the strength of this code. Lost communication is a symptom of power, ground, wiring or network trouble far more often than it is a failed controller, and a replacement will be just as silent on a broken circuit.
How much does it cost to fix U0105?
There is no honest single figure for U0105, and any page that gives you one is guessing. The code names a circuit or a failed monitor, not a part — the same code can be a chafed wire, a connector full of water, or the component itself, and those are three very different bills.
Related OBD-II codes
These nearby injector entries can help compare wording and pin down the fault area.